<!DOCTYPE html>
<html>

	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript">
			var p1=prompt("请输入第一个数："+"");
			var p2=prompt("请输入第二个数："+"");
			var sign=prompt("请输入运算符："+"");
			var num1=parseFloat(p1);
				var num2=parseFloat(p2);
				var result=0;
				switch (sign=){
					case "+":
					
						break;
							case value:
						break;
						
							case value:
						break;
							case value:
						break;
					default:
						break;
				}
			
		</script>
	</head>

	<body>
	</body>

</html>